Weight lifting and transfer device

ABSTRACT

A light weight apparatus for the lifting and if desired movement of various loads is shown, the apparatus being capable of being rapidly dis-assembled into components each of which can be readily carried by a man, so that transport into confined spaces, or through restricted passages, is easily accomplished. The apparatus includes a boom section, including a slidable sleeve segment for alteration of length and means for fixing a desired length; a leg-socket device also slidable positionable on the boom, and having a pair of downwardly extending, angularly displaced leg sockets for receiving a pair of legs, each including a foot portion having a rubber tired wheel as the ground contacting element and including a telescoping strut piece so that the length of the leg assembly can be altered, means being provided for fixing each leg at the desired length. A winch and an operator&#39;&#39;s seat are attached to the lower segment of the boom, a cable or rope operated by the winch running over a pulley in the upper extremity of the boom assembly and terminating at a load hook. The variable lengths of the boom and legs, and the variable positions possible of the leg-socket device make it possible to assemble the apparatus in a large number of configurations providing lifting ability ranging from a low mechanical advantage up to a configuration inherently stable in that the load weight point is within the confines of the triangle defined by the ground contact points of the two wheels, and the lower extremity of the boom assembly.

United States Patent [191 McCarstle WEIGHT LIFTING AND TRANSFER DEVICE [76] Inventor: Cecil M. McCarstle, 11734 Fairhauen Dr., Baton Rouge, La. 70815 [22] Filed: Aug. 31, 1970 [21] Appl. No.: 68,420

Primary ExaminerEvon C. Blunk Assistant Examiner-Douglas D. Watts Attorney, Agent, or FirmLewis R. Krieg [57] ABSTRACT A light weight apparatus for the lifting and if desired movement of various loads is shown, the apparatus [451 Apr. 2, 1974 being capable of being rapidly dis-assembled into components each of which can be readily carried by a man, so that transport into confined spaces, or through restricted passages, iseasily accomplished. The apparatus includes a boom section, including a slidable sleeve segment for alteration of length and means for fixing a desired length; a leg-socket device also slidable positionable on the boom, and having a pair of downwardly extending, angularly displaced leg sockets for receiving a pair of legs, each including a foot portion having a rubber tired wheel as the ground contacting element and including a telescoping strut piece so that the length of the leg assembly can be altered, means being provided for fixing each leg at the desired length. A winch and an operators seat are attached to the lower segment of the boom, a'cable or rope operated by the winch running over apulley in the upper extremity of the boom assembly and terminating at a load book. The variable lengths of the boom and legs, and the variable positions possible of the leg-socket device make it possible to assemble the apparatus in a large number of configurations providing lifting ability ranging from a low mechanical advantage up to a configuration inherently stable in that the load weight point is within the confines of the triangle defined by the ground contact points of the two wheels, and the lower extremity of the boom assembly.

7 Claims, 4 Drawing Figures PATENTEBAPR 2 m4 3,801,069

' sum 1 or 2 v INVENTOR. CECIL M. McCARSTLE ATTORNEY PATENTED 2 I974 SHEETEUFZ INVENTOR, CECIL M. McCARSTLE ATTORNEY;

1 WEIGHT LIFTING AND TRANSFER DEVICE SUMMARY OF THE INVENTION Background of the Invention and the Prior Art Problem This invention is in the field of material handling equipment. More particularly, the invention concerns apparatus, usually man-powered, for lifting various loads of moderate to intermediate weight, typically, from about 100 to 500 pounds.

Cranes, derricks, lift trucks, and other lifting apparatus are available in a wide variety of designs. Generally, the devices or machines commercially available are more-or-less specialized and designed for high capacity performance, either in the sense of the weight of the loads which can be carried, or in the rapidity of lifting or other movement to be imparted. No apparatus has thus far been provided for handling loads which just exceed the safe carrying capacity of a man, or several men, and particularly when such loads must be lifted from and moved from awkward or relatively inaccessible positions.

Material or equipment handling problems of the above defined character are very frequently encountered in the building construction or maintenance field. The problems can be more specifically described with reference to air. conditioning equipment, which of course has enjoyed a tremendous growth in the last twenty years. Central air conditioning and heating equipment is now almost universally included in the construction of most public buildings, multi-unit residential construction, stores, office buildings and the like. The commercial scale equipment used for such installations is almost invariably mounted on the top floor or roof of the structure. The equipment usually includes condensers, compressors, cooling towers, ductwork, and the electric motor drives for the various units.

The individual units or motors for air conditioning installations are not enormously heavy, but frequently are sufficiently heavy that they cannot be safely lifted by one man, or even two men. Added to the weight problem is the fact that the designs of an installation are not intended to provide for easy removal for shop servicing or replacement with new units. The original placement of equipment units of the type described presents no great problem, as it is usually done when the structure is being erected, when long reach, high capacity motorized cranes or derricks are at hand. The removal of, or installation of, equipment in a completed structure is another matter, however. At such times, the service or maintenance man is faced with the necessity of, for example, lifting a motor or compressor weighing two or three hundred pounds from its mounting on a relatively inaccessible platform on the roof of a four or five story building, and safely removing it to ground level. The rental of high lift cranes is quite expensive, and frequently such rental equipment is not available when needed. In addition, occasionally the location of the equipment to be moved is such that it would not be accessible to a motorized crane, as for example, when the equipment is not close to the parapet of a roof.

It will be understood that the above described problem or need in connection with the maintenance of air conditioning equipment is illustrative. Similar load and being rapidly assembled in any of a variety of configurations which are tailored to the demand of a particular operation.

OBJECTS OF THE INVENTION A general object of the invention is to provide a new and improved lifting apparatus. A further object is to provide apparatus for lift and/or transverse movement, which can be rapidly disassembled in segments or subassemblies each of which are relatively compact and of light weight. An additional object is to provide apparatus of the type described which can be assembled in any of a large number of configurations according to load needs so that a mechanical advantage in lifting can be suitably applied according to particular needs so that counterbalancing needs can bevaried, and, in fact,'an inherently stable configuration can be supplied according to which no counterbalancing is required. An additional object is to generally advance the art.

GENERAL DESCRIPTION The apparatus of the invention is a lifting and moving device constructed of readily separable parts or subassemblies each of which are readily transported by a single individual. When assembled, any of a large variety of different configurations of structure can be used, these varying in function from apparatus in which a counterweight for the object being lifted is provided by the operator himself, if desired, to an inherently stable configuration in which the weight point is at a position within the triangle defined by the three points of contact of the apparatus with the ground or other supporting surface.

The several parts of the apparatus include a boom assembly or section, a leg socket device, and two leg assemblies, all as more fully particularized below. The boom assembly includes segments arranged for telescopic sliding fit with each other and including a bottom segment to which is attached a winch means and an operators seat, both generally adjacent the btoom extremity of the boom. A top segment of the boom as sembly has a pulley at its upper end, over which runs a cable, rope or chain from the winch means. The said cable terminates in a load hook or similar device for making connection with the load. Means are provided for clamping or fixing the several parts of the boom assembly to provide the desired operating length.

Slidably associated with the top segment of the boom, usually by a sleeve member encircling the tubular top segment, is'a leg socket apparatus. It includes, in addition to the portion for making sliding fit on the boom portion, and projecting therefrom, two leg attachment members, desirably in the form of relatively short tubular socket members for receiving the upper ends of downwardly extending leg assemblies. These leg attachment members are angularly displaced from each other at an angle of, for example, from about 40 to 60, and impart =such angle of spread to the leg a's-' an acute angle of 75 to 85 to the axis of the boom assembly.

The two leg assemblies project downwardly from the leg attachment device to the ground or supporting surface and support the top end of the boom in an elevated position, for lifting purposes. Each leg assembly includes a foot piece and an extension piece slidably engaging the foot piece but capable of being positioned by fastening means in any of a number of positions to provide the assembly with the desired fixed length, for a particular apparatus configuration. The foot piece of each leg assembly includes a preferably tubular member terminating at the lower end with a wheel support holding a ground engaging wheel having a relatively soft surface, viz., as provided by a pneumatic tire. The leg extension piece desirably telescopically or by other 'slidable engagement attaches to the foot piece, and the precise length of the leg assembly is fixed by suitable fastening means at any of a number of determinable, fized positions. The upper end of each extension piece is attached to its respective leg attachment member, and fastening means are provided for fixing this attachmentfor use of the apparatus.

As indicated, the apparatus includes fastening means for, respectively, maintaining a desired, selected length of the assembled boom, the position of the leg attachment device on the boom length, for attaching the leg assemblies to said device, and for maintaining the desired lengths of the leg assemblies. Various fastening means are suitable, depending on the precise design of the boom and leg elements. In most embodiments, tubular sections of circular cross section are eminently suitable for these components, and in such instances it is found that a series of matching holes in telescoic'ally connected tubular elements provide for the desired variations in dimensions or positions, with steel pins inserted in paired holes for fastening the parts.

The complete apparatus can be assembled in a substantial number of specific configurations according to the job needs. Thus, for a long reach" the leg attachment device is positioned relatively remote from the upper .extremity of the boom assembly, and the leg members are in a short, or relatively short position. In this fashion, the boom can be projected out over a roof edge, for example, for purposes of safely lowering a load to the ground. In configurations of this character, the weight of the operator serves to counterbalance the load weight, and the capacity of the apparatus obviously depends on the mechanical advantage applied by the relativesegments of the boom length and the position of the ground engaging wheels. For the greatest capacity in fact for an inherently stable configuration the apparatus is assembled so that the load point is within the area of the triangle established by the three points of support, viz., the two wheels and the lower'extremity of the boom. Despite this inherently stable or tripod position, the apparatus is still adapted to raise and lower objects in at least some situations in which the load must be projected beyond the roof edge, or must be placed on or removed from a platform providing a surface differing in elevation from the support surface such as a roof deck or the ground.

The principles of construction and of operation of the apparatus of the invention will be illustrated in more detail by the figures and by the detailed description hereafter given.

FIGURES The figures illustrating a preferred embodiment of the invention and the manner of its operation include FIG. 1, a side view elevation of a particular embodiment assembled in a typical, frequent work configuration,

FIG. 2, part sectional view of the front of the embodiment of FIG. 1, on the line 22,

FIG. 3, showing in section a typical connection of parts of the apparatus providing forvariable positions, and showing a suitable device for registering and fixing the connecting parts in a particular position,

FIG. 4, a side elevation, in slightly reduced size, of the embodiment of FIG. 1 assembled in the heretoforementioned configuration providing an inherently stable lifting function.

DETAILED DESCRIPTION Reference is made to FIG. 1, showing a side or elevation of the apparatus assembled for providing a mechanical advantage of, roughly, four to one, and providing a moderate over-reach. By mechanical advantage, as used herein to describe the function of the various configurations of which the apparatus is capable, is meant the approximate distance ratio of the horizontal distance from the operator to the line of contact of the wheels with the supporting surface, to the distance from said line to the load point. By over-reach, as used herein, is meant the distance the load point is beyond the wheel contact line.

Reference should also be made to FIG. 2, a view in part section 'of the front that is, the loading end of the apparatus in the assembled configuration of FIG. 1, on the line 22. In the embodiment of FIGS, 1 and 2, the boom assemnly 10 includes three tubular elements, the seat segment 11, a boom sleeve 21, and an uppermost or spar segment 31. For breaking down the apparatus into smaller sized, relatively light weight parts, in this embodiment the boom sleeve 21 can be separated from both the seat segment 11 and the spar segment 31. It is preferred that these components be tubes of circular cross-section, but it will be apparent that the circular configuration is not absolutely essential. The sleeve 21 is sized to slide smoothly around the tube 12 of the seat segment 11, and also the spar segment 31, which in this instance has the same diameter as the tube 12 of the seat segment 11. A leg retention device 41 is positioned on the spar segment 31, above the extremity of the sleeve 21.

A bracket 14 is attached at the lower end of the tube 12. Projecting from it is an adjustable standard 19, which supports an operators seat 13, usually a stamped metal seat as is used on tractors or the like. A winch 17 for operating the cable 34 is attached to the tube 12 of the seat segment 11 in a position slightly removed from the seat 13 and at a convenient distance for an operator on the seat 13 to grasp the winch handle 18 or the desirable locking-release control, not shown, of the winch. An end skid 15 is attached at the lower most end of the tubes. Projecting from the body or sleeve 42 of the leg retention device 41 are two leg sockets 43,, 43 These are relatively short tubular elements for receiving the upper ends of tubular leg extensions 69,, 69 The leg sockets 43,, 43 form an acute angle which is not critical but which desirably is in therange of to 65. The axes of the leg sockets 43,, 43 are both in the same plane, generally transverse to the axis of the boom assembly 10. In preferred embodiments as shown, the said plane is tilted slightly toward the lowermost end of the boom assembly, that is, toward the winch and the operators seat 13. In other words the plane of the leg assemblies 60,, 60 forms an acute angle with the axis of the boom assembly below that assembly and toward the lower end thereof. The particularly beneficial effect of this configuration will be more particularly noted hereinafter. This preferred angle is about 75 to 85 Completing the leg assemblies are foot pieces 61,, 62 These units comprise tubular sections 62,, 62 which support yokes 63,, 63 and are sized to have an internal diameter for telescopically receiving a part of the length of the leg extensions 69,, 69 The wheels 65,, 65 are journalled on axles 64,, 64 positioned through the branches of each of the yokes 63,, 63

The wheels 65,, 65 include a metal hub and a pneumatic tire in the most preferred embodiments and surprisingly they perform a supplemental bracing function when the apparatus is in the assembled configuration as is illustrated in FIG. 2.

It is clearly essential to provide for positive locking of the several telescoping sections at any of the desired fixed positions, and a preferred means is shown in FIG. 3, which is a view of a section of the boom assembly 10 at line 3-3. The telescoping fit of the tubular segment 12 is shown inside the sleeve member 21. Uniform sized holes 9, 22, are drilled in the sleeve 21 and the bottom tube 12, and are carefully aligned at right angles to the axis of the tubes. A lock pin 24 slides into the paired holes, sufficient clearance being provided for digital removal or insertion. Removal is facilitated by a ring handle 25. A spring loaded button 26 near the end of the pin 24 assures that the .pin would be retained in place even ifit is not jammed in place by a compressive force on the assembly. It also assures that the lock pin 24 could be inserted in a single hole in a tube of the disassembled apparatus for retention until the apparatus is set up again at another job site.

Lock pin arrangements as above described are used at several different locations in this embodiment. Thus, the position of the extension spar 31 in the sleeve 21 is established by the lock pin 23. The lock pin 23 fits through a pair of the matching holes of the type already described, in the sleeve and in the spar 31, which has other holes 33,, 33 33,, 33 33 in a regularly spaced series in addition to the one occupied by pin 23. The position of the leg attachment device 41 is maintained at a desired point by the lock pin 44. Similarly, the leg assemblies 60,, 60 are fixed in place with respect to the boom assembly 10 by lock pins 46,, 46 through pairs ofmatched holes in the walls of the leg sockets 43,, 43 and the ends of the leg extensions 69,, 69 received in the sockets. In addition to the holes in the leg sockets 43,, 43 for accommodating the lock pins 46,, 46 when the apparatus is assembled as in FIGS. 1 and 2, supplemental holes 47,, 47 can be provided which are at right angles thereto. Thus, when desired, each of the leg assemblies 60,, 60 can be fastened in place with the wheel thereof positioned to roll on a path at right angles to the center line of the apparatus. This arrangement is of particular value when it is desired, for convenience or because of space limitations, to transfer a lifted load from its position directly at right angles to the center line of the apparatus, without the need of swinging the entire apparatus around.

With respect to the fastening of the leg extensions 69,, 69 in fixed telescoped position with respect to the tubes 62,, 62 of the foot pieces 61,, 61 lock pins as already described can be used. Preferred means, however, are eye bolts 67,, 67 projecting through matched holes in both walls of both the tubular sections 62,, 62 and of the leg extensions 69,, 69 The eye bolts 67,, 67 are secured in place with wing nuts 70,, 70 The use of eye bolts and wing nuts permits assembly or disassembly without the use of tools, because the eyes of the bolts as well as the wing nuts can be grasped by hand for easy threading. Further, the eyes are capable of performing an additional function, in that they can serve as anchorages for a reinforcing tension member, not shown, connecting the two leg assemblies 60,, 60

A series of holes 58,, 58 in the leg extensions 69,, and a comparable series 59,, 59 in leg extensions 69 in addition to the hole not shown, in use, according to FIG. 1 and 2, are provided. The spacing of this series is usually closer together than the spacing of the previously mentioned series 33,-33 in the spar 31.

It is believed that the functioning and use of the apparatus will be self-evident at least in part from the fore going description, but certain features and advantages should be further noted. In the configuration generally illustrated by FIGS. 1 and 2, the weight of the apparatus itself provides appropriate counterbalancing for small or moderate loads. In such instances, after the operator has lifted the load to a free position, he can leave the operating position, having locked the winch setting. The lower end of the boom assembly- 10 can then be raised slightly from the ground and the apparatus and suspended load can be easily trundled to a fresh position. A maneuvering handle 16 attached to the tube 12 is provided for readily grasping the lower end of the boom assembly 10 and for maneuvering the apparatus.

When heavier loads are being carried, a two-man operation is usually desirable. In such instances, that is, when the load is sufficiently large that the weight of the boom will not provide counterbalancing, a second man can hold the lower end of the boom on the ground while the operator dismounts, then both can safely maneuver the apparatus and load to a new position.

As an alternative to a two-man operation, counterbalancing, in the form of any convenient dense objects, can be supplied by temporary wiring or lashing to the lower end of the boom assembly. Experience is rapidly gained on the most convenient modes of operation.

As previously mentioned, a particular virtue of the apparatus is that it is readily assembled in a configuration which is inherently stable, and such a mode of assembly is illustrated by FIG. 4. This figure is again a side elevation of the apparatus, as is FIG. 2. In this assembly, however, the leg socket piece 41 and the spar 31 are positioned generally in the same position as in the configuration of FIG. 1 ancl.2. The leg assemblies 60,, however, are lengthened to a great extent by means of substitution of longer leg extension pieces 72,, 72 than the leg extensions 69,, 69 employed in the configuration of FIG. 1 and 2.

The pulley 32 is not only elevated, but its position and the lateral position of the load hook 35 is shifted rearwardly, i.e., toward the seat segment 11 of the boom assembly, sufficiently so that it is between the line of contact of the wheels 65,, 65 and the lower end of the boom assembly l0. With this configuration, then, the apparatus in substance is inherently stable in that it has the geometric effect of a tripod, the load being lifted from the apex thereof. This configuration is of course particularly useful for loads near or at the capacity of the apparatus. The inherently stable character assures that no special precautions would be needed to provide a load counterbalancing action. The arrangement is also particularly useful when it is necessary for one man to handle a load of a size that ordinarily requires two men to handle with the apparatus.

A further feature of theconfiguration of FIG. 4 is that transverse or lateral movement of the apparatus and load can be accomplished without loss of the inherent stability. As described already, preparatory to transverse movement, the .lower end of the boom assembly is lifted slightly from the ground so only the wheels are in contact with the ground. Using, in effect, the boom as a handle, the apparatus and the load can be moved horizontally. With the apparatus as arranged in FIG. 4, it is clear that the lower end of the boom 10 can be raised slightly, but nevertheless the load hook 35, i.e., the load point, will still be between the center line of the wheels and the lower end of the boom. Again, then, the inherently stable function of a tripod is attained.

From the foregoing description the necessary functional interrelationships of the parts of the apparatus will be readily understood. It will also be clear that the precise sizes of the various parts is not critical and that various sized embodiments are readily provided for different classes of service. in one particular embodiment, of a size particularly useful in building maintenance work, the total boom length can be varied, in increments from as low as about l 1 feet to up to 16 feet. The elevation of the pulley at the end of the boom can be as low as 5 feet up to, roughly, 12 feet.

When the boomand leg parts are made of tubular sections, as specifically described, standard pipe sizes can be used and by proper selection, suitable (it can be obtained for telescopic sliding relationship without the necessity ofspecially machined parts. Thus, for example, 3 inch nominal sized pipe can be used for the spar section 31, and for the tubular portion 12 of the seat segment 11, and 3-% inch pipe for the sleeve 21, as well as for the tubular portion 42 of the leg support device 41.

For obtaining superior mobility and lightness, it is preferred to make the tubular elements of aluminum. in a typical embodiment, the entire apparatus will weigh less than 200 pounds, and the heaviest of the parts, when it is disassembled, will weight appreciably less than 100 pounds. It is therefore very easy for the apparatus to be quickly disassembled, transported, and reassembled by one man.

As previously noted, and reverting to PK]. 1 and FIG. 2, provision is made in' preferred embodiments for positioning the wheels at rightangles to the axis of the boom. This is accomplished by rotating the leg assemblies 60,, 60 through right angles and reinserting the locking pins 46,, 46-; through the alternate holes 47,, 47 into the corresponding holes in the upper extremities of the leg extensions 69,, 69 It is seen that, with the leg assemblies in this position, that forward and backward movement of the apparatus is prevented.

This is a particularly benefiicial feature if the apparatus is to be mounted on an inclined surface. A further benefit of this alternative feature of the leg assemblies is achieved by positioning only one assembly to align the wheel at right angles to the boom, the other being in the illustrated position parallel to the boom. in this configuration, forward and backward movement is restricted by only one wheel. Transport of the load would then be possible in an arced path, by rotating the apparatus about the contact point of the wheel at right angles to the boom.

it will be apparent that a very large number of configurations of the apparatus are possible in addition to those specifically illustrated by the arrangements of FIGS. 1 and 2, and of H6. 4. Thus, without changing the leg extension pieces, (e.g., 69,, 69 of FIG. 1 and FIG. '2) a different set of proportions can be obtained by independent change of (a) the lengths of the leg assemblies, (b) the overall length of the boom assembly or (c) the position of the leg retention device on the boom assembly. It is clear that any two, or all three, of these changes can be made concurrently to achieve a particular desired selection of proportions.

As previously mentioned, the preferred angular disposition of the plane of the leg assemblies is at an acute angle to the axis of the boom assembly. This relation is particularly beneficial in reducing the stress on the parts of the leg retention device in certain configurations. More specifically, when the apparatus is assembled to raise the pulley end, it will be seen (see FIG. 4) that a greater stress component is established on the joints, of the leg receiving parts, to the body of the leg retention device. This stress is of course proportionately reduced when the angle of the plane of the leg assemblies is lower. The'preferred range of to is an optimum range for maximum versatility.

To achieve maximum strength, the leg assemblies are positioned, in the manner previously described, to right angles to the center line of the assembly, and a' reinforcing wire or bar is used as a connection between the eyes of the eye-bolts which position the foot assemblies and the leg extensions. The tendency of the legs to spread under load is then resisted by said reinforcement. The tendency of the leg assemblies to spread under load, with respect to the boom, is in this instance counteracted by the resistance of the tires to sideways movement.

From the foregoing description of the apparatus of my invention it will be seen that it provides a high degree of versatility so that the configuration and capability can be readily accommodated to the demands of a particular function. Numerous variations in construction are possible, the invention being limited only as defined by the appended claims.

What I claim as my invention is:

l. A hoisting apparatus including a boom assembly having a variable length boom of at leasttwo connected segments, an operators seat and a winch generally adjacent the lower end of the boom, a pulley at the other and normally elevated end for guiding a cable from the winch, and releas-- able fastening means for maintaining the boom at a chosen length, leg attachment device including a body member slidably attached to the boom and two leg receiving arms downwardly extending at an angular disposition to each other and in a plane horizontally at right angles to the boom axis, releasable means to fasten the device at any of a number of points along the boom, and releasable means to fasten leg assemblies to and aligned with said downwardly extending arms, and

two leg assemblies each having a variable length and at least two connected segments and releasable fastening means for maintianing each leg assembly at a chosen length, one of the leg segments being an upper extension segment received by the leg receiving arm and another being a foot segment having a supporting wheel at the lower end thereof, the apparatus being capble, by change of the position of the leg attachment, the length of the boom, and the lengths of the leg assemblies, ofa first type of configuration in which the pulley is further horizontally from the lower end of the boom assembly than is the center line of the wheels whereby counterbalancing at the lower end is required for lifting, to a second type of configuration at which the pulley is between the center line of the wheels and the lower end of the boom, whereby an inherently stable lifting ability is provided not requiring any counterbalancing.

2. The apparatus of claim 1 further defined in that the boom assembly includes a seat segment having a tubualr section on which is mounted the winch and the operators seat, a tubular sleeve, and a tubular spar segment, the tubular spar segment and the tubular section having the same diameter and being received in opposite ends of the sleeve, means for maintaining the said I tubular section in the sleeve comprising a pair of matching holes in the walls of the sleeve and the tubular section and a pin through said holes, the fastening means for maintaining the boom assembly at a chosen length including a hole in the wall of the sleeve portion receiving the said spar segment, a series of spaced apart holes in the wall of the spar segment, each capable of matching, and one positioned to match the hole in the sleeve wall, and forming a second pair of matching holes, and a pin through said pair of holes.

3. The apparatus of claim 1 further defined in that the boom assembly includes a tubular spar segment comprising the upper end thereof and the leg attachment device includes a tubular body member, slidable over and positioned on said spar segment, and the means to fasten the leg attachment device comprises a series of spaced apart holes in the wall of the spar segment, and a hole in the wall of said tubular body mem ber capable of matching with any of said series of spaced apart holes and form thereby a pair of matched holes, said device being positioned to form such a pair of holes, and a locking pin inserted through such pair of holes.

4. The apparatus of claim 3 further defined in that leg receiving arms of the leg attachment device comprise relatively short tubular sections, the upper extension segment of each leg is a tube receivable in the leg receiving arm, the means for fastening said legs comprise at least one pair of matching holes in the walls of each receiving arm and the wall of the leg extension received therein and a locking pin inserted through such a pair of matching holes.

5. The apparatus of claim 4 further defined in that the means for fastening the legs includes at least two holes in the wall of each of said receiving arms, peripherally spaced at right angles whereby each leg assembly can be positioned in either of two positions at right angles to each other. I

6. The apparatus of claim 3'further defined in that the leg receiving arms of the leg attachment device comprise relatively short tubular segments, the foot segment of each leg comprises a tubular section of the same diameter as the leg receiving arms, the upper extension segment of each leg is a tubular section sized to be telescopically received at its ends by the leg receiving arms and the tubular section of the foot segment, the fastening means for maintaining the legassembly at a chosen length comprising a hole in the wall of the foot segment, a series of spaced apart holes in the wall of the leg extension, each capable of being matched with the hole in the wall of the foot segment to form a pair of aligned holes, and one of said series of holes is so matched, and a locking, pin through said pair of matched holes.

7. A hoisting apparatus including a variable length boom assembly comprising a tubular spar segment having a pulley at one end thereof,

' a tubular sleeve, and a seat segment comprising a tubular member and a winch means and an operators seat mounted thereon, the spar segment and the tubular member of the seat segment being telescopically received in part in opposite ends of the sleeve, the spar segment having a series of holes in the wall thereof spaced along the spar length, the sleeve having a hole in the wall thereof at each end and the tubular member of the seat segment having a hole in its wall in the portion received in the sleeve, said hole being positioned to match with the hole in the receiving end of the sleeve, and a removable locking pin through said matching holes, the holes in the spar being capable of individually matching with the hole in the receiving end of the sleeve, and the spar segment being positioned to form such a pair of matching holes, and a removable locking pin inserted through said pair of holes,

a leg attachment device including a tubular body member slidable over and positioned on the spar 7 segment of the boom assembly, said tubular body member having a hole in the wall thereof capable of matching a hole in the series of holes in thewall with a hole in the wall of a tubular leg extension received therein as hereafter defined, and two leg assemblies each comprising an extension segment and a foot segment, the foot segment comprising a tubular section of the same diameter as the arm of the leg attachment device, and having an aligned pair of holes through its walls, the leg extension being a tube sized to be and received at its ends by the said arm and the tubular section of the foot segment, the leg extension having a hole in the wall of the upper portion in the said arm, positioned to match the hole in the wall of the said arm vice, the length of the spar received in the sleeve, and the length of the leg assemblies, of a first type of configuration in which the pulley is further horizontally from the lower end of the boom assembly than is the center line of the wheels whereby counterbalancing at the lower end is required for lifting, to a second type of configuration at which the pulley is between the center line of the wheels and the lower end of the boom, whereby an inherently stable lifting ability is provided not requiring any counterbalancing. 

1. A hoisting apparatus including a boom assembly having a variable length boom of at least two connected segments, an operator''s seat and a winch generally adjacent the lower end of the boom, a pulley at the other and normally elevated end for guiding a cable from the winch, and releasable fastening means for maintaining the boom at a chosen length, a leg attachment device including a body member slidably attached to the boom and two leg receiving arms downwardly extending at an angular disposition to each other and in a plane horizontally at right angles to the boom axis, releasable means to fasten the device at any of a number of points along the boom, and releasable means to fasten leg assemblies to and aligned with said downwardly extending arms, and two leg assemblies each having a variable length and at least two connected segments and releasable fastening means for maintianing each leg assembly at a chosen length, one of the leg segments being an upper extension segment received by the leg receiving arm and another being a foot segment having a supporting wheel at the lower end thereof, the apparatus being capble, by change of the position of the leg attachment, the length of the boom, and the lengths of the leg assemblies, of a first type of configuration in which the pulley is further horizontally from the lower end of the boom assembly than is the center line of the wheels whereby counterbalancing at the lower end is required for lifting, to a second type of configuration at which the pulley is between the center line of the wheels and the lower end of the boom, whereby an inherently stable lifting ability is provided not requiring any counterbalancing.
 2. The apparatus of claim 1 further defined in that the boom assembly includes a seat segment having a tubualr section on which is mounted the winch and the operator''s seat, a tubular sleeve, and a tubular spar segment, the tubular spar segment and the tubular section having the same diameter and being received in opposite ends of the sleeve, means for maintaining the said tubular section in the sleeve comprising a pair of matching holes in the walls of the sleeve and the tubular section and a pin through said holes, the fastenIng means for maintaining the boom assembly at a chosen length including a hole in the wall of the sleeve portion receiving the said spar segment, a series of spaced apart holes in the wall of the spar segment, each capable of matching, and one positioned to match the hole in the sleeve wall, and forming a second pair of matching holes, and a pin through said pair of holes.
 3. The apparatus of claim 1 further defined in that the boom assembly includes a tubular spar segment comprising the upper end thereof and the leg attachment device includes a tubular body member slidable over and positioned on said spar segment, and the means to fasten the leg attachment device comprises a series of spaced apart holes in the wall of the spar segment, and a hole in the wall of said tubular body member capable of matching with any of said series of spaced apart holes and form thereby a pair of matched holes, said device being positioned to form such a pair of holes, and a locking pin inserted through such pair of holes.
 4. The apparatus of claim 3 further defined in that leg receiving arms of the leg attachment device comprise relatively short tubular sections, the upper extension segment of each leg is a tube receivable in the leg receiving arm, the means for fastening said legs comprise at least one pair of matching holes in the walls of each receiving arm and the wall of the leg extension received therein and a locking pin inserted through such a pair of matching holes.
 5. The apparatus of claim 4 further defined in that the means for fastening the legs includes at least two holes in the wall of each of said receiving arms, peripherally spaced at right angles whereby each leg assembly can be positioned in either of two positions at right angles to each other.
 6. The apparatus of claim 3 further defined in that the leg receiving arms of the leg attachment device comprise relatively short tubular segments, the foot segment of each leg comprises a tubular section of the same diameter as the leg receiving arms, the upper extension segment of each leg is a tubular section sized to be telescopically received at its ends by the leg receiving arms and the tubular section of the foot segment, the fastening means for maintaining the leg assembly at a chosen length comprising a hole in the wall of the foot segment, a series of spaced apart holes in the wall of the leg extension, each capable of being matched with the hole in the wall of the foot segment to form a pair of aligned holes, and one of said series of holes is so matched, and a locking pin through said pair of matched holes.
 7. A hoisting apparatus including a variable length boom assembly comprising a tubular spar segment having a pulley at one end thereof, a tubular sleeve, and a seat segment comprising a tubular member and a winch means and an operator''s seat mounted thereon, the spar segment and the tubular member of the seat segment being telescopically received in part in opposite ends of the sleeve, the spar segment having a series of holes in the wall thereof spaced along the spar length, the sleeve having a hole in the wall thereof at each end and the tubular member of the seat segment having a hole in its wall in the portion received in the sleeve, said hole being positioned to match with the hole in the receiving end of the sleeve, and a removable locking pin through said matching holes, the holes in the spar being capable of individually matching with the hole in the receiving end of the sleeve, and the spar segment being positioned to form such a pair of matching holes, and a removable locking pin inserted through said pair of holes, a leg attachment device including a tubular body member slidable over and positioned on the spar segment of the boom assembly, said tubular body member having a hole in the wall thereof capable of matching a hole in the series of holes in the wall of the spar, to form a pair of matching holes, the leg attachment device being positioned to provide such a pair of matchinG holes and a removable locking pin inserted in said pair of holes, the body members having two downwardly extending leg receiving arms each being a relatively short tubular section, said arms projecting at an acute angle to each other in a plane horizontally at right angles to the axis of the boom assembly, each of said arms having at least one hole in its wall for matching with a hole in the wall of a tubular leg extension received therein as hereafter defined, and two leg assemblies each comprising an extension segment and a foot segment, the foot segment comprising a tubular section of the same diameter as the arm of the leg attachment device, and having an aligned pair of holes through its walls, the leg extension being a tube sized to be and received at its ends by the said arm and the tubular section of the foot segment, the leg extension having a hole in the wall of the upper portion in the said arm, positioned to match the hole in the wall of the said arm and a removable locking pin inserted through the thus formed pair of holes, the leg extension have a series of spaced apart double holes through its walls each of said series capable of matching the holes in the walls of the tubular section of the foot segment, and positioned with one pair so matched, and a bolt inserted through said double pair of holes, the foot segment further having a pneumatic tired support wheel attached thereto, said apparatus being capable by change of at least one of the factors: the position of the leg attachment device, the length of the spar received in the sleeve, and the length of the leg assemblies, of a first type of configuration in which the pulley is further horizontally from the lower end of the boom assembly than is the center line of the wheels whereby counterbalancing at the lower end is required for lifting, to a second type of configuration at which the pulley is between the center line of the wheels and the lower end of the boom, whereby an inherently stable lifting ability is provided not requiring any counterbalancing. 